Heat exchanger



INVENTOR. RIC/{A130 G. LYALL BY WwaW ATTORNEYS United States Patent 3,254,709 HEAT EXCHANGER Richard G. Lyall, 27 Darwin Drive, Buflt'alo 26, N.Y. Filed July 30, 1963, Ser. No. 298,685 6 Claims. '(Cl. 165-158) ferential flanges or enlargements on the shell member or the head member or both. The present invention provides an arrangement wherein a tie rod extending axially through the heat exchanger, or several such tie rods, performs the function of maintaining the several heat exchanger body components in assembled relation.

This general mode of assembly is illustrated herein in one form by way of example. The general shell or body member of a heat exchanger and the head member thereof are releasably secured to an intervening tube sheet by a tie rod which is fixed to the tube sheet and extends in opposite directions therefrom through the body member and the head member.

Various other novel details of construction and the advantages inherent in the heat exchanger constructions 'of the present invention arepointed out in detail in conjunction with the following description of a typical embodiment of the invention. While only one embodiment of the present invention is illustrated in the accompanying drawing and described in the following specification, it is to be understood that such embodiment is by way of example only and to illustrate the principles of the present invention, the scope of which is limited only as defined in the appended claims.

In the drawing: 7

FIG. 1 is.a longitudinal cross sectional view through one form of the heat exchanger of the present invention; and

FIG. 2 is a cross sectional view on the line II-H of .FIG. 1.

Referring to FIG. 1 of the drawing, the tube sheet which forms the general or central support for the heat exchanger in this embodiment is designated 10 and a central tie rod 11 passes through the tube sheet and extends in opposite directions therefrom. In the present instance tie rod 11 is threaded from the left hand end as at 12 in FIG. 1 to engage threads in tube sheet 10. In addition a tack weld may be employed to seal the joint against leakage and to prevent relative rotation of the tie rod and tube sheet.

A hollow cylindrical shell 14 has a cover 15 fixed thereto at one end, as by welding, and this need be only a seal weld and not a strength weld, since the tie rod carries the internal loading. The open end of shell 14 seats in a groove 16 in tube sheet 10. In the illustrated example an O-ring 17 seals the joint between shell 14 and tube sheet 10.

A central axial opening in cover 15 of shell 14 fits over the extending portion of tie rod 11 and a cap nut 18 threads onto the tie rod to clamp shell 14 securely against tube sheet 10 in pressure-tight relationship. An O-ring or other gasket or sealing device in nut 18 seals the interior thereof so that the tie rod may pass freely through cover 15 without danger of leakage. Thus the shell 14 and integral cover 15 are securely held in pressuretight relation with respect to tube sheet 10 by this single attachment which is readily applied and removed and which, moreover, affords a holding force directly along the axis of the tube sheet and shell.

3,254,709 Patented June 7, 1966 In FIG. 1 the numeral 19 designates a pin fixed to and ice projecting from tube sheet 10 into a perforated or slotted lug 20 which may be Welded to shell 14. In this embodiment the pin 19 and lug 20 prevent relative rotation between the tube sheet and shell and thus insure that the shell 14 occupies a predetermined angular position with respect to tube sheet 10 and the head member of the assembly so that the several entry and discharge passages are certain to be in predetermined angular relationship, for example in a common plane as illustrated in-FIG. 1.

In FIG. 1 the numeral 21 designates a cup-shaped head member which abuts at its rim portion with the opposite side of tube sheet 10 with reference to shell 14. A suitable gasket 22 may be interposed or an O-ring may be recessed into either the head member or tube sheet or partly in each. A locating pin 23 on tube sheet 10 extends into an opening in a projection on pass plate 24 of head member 21 are designated 28 and 29.

The left hand projecting threaded portion of tie rod 11 as viewed in FIG. 1 passes through head member 21 and a cap nut 30 engages the'threaded end of tie rod 11 to secure the head member against tube sheet 10 in a secure, simple and effective manner. Here again an O- ring 31 which is 'set into nut 30 or another gasket or sealing device is provided as in the case of nut 18 and for the same purpose.

A series of U-tubes designated generally by the numeral 35 have their ends disposed in corresponding openings in tube sheet 10, one end of each U-tube being at each side of the pass plate 24 of the head member 21. The U- tube arrangement and distribution shown in FIGS. 1 and 2 is merely by way of example and forms no specific part of the present invention.

While a single tie rod serves to retain the entire heat exchanger assembly, it will be noted either of the nuts 18 or 30 may be removed to release the adjacent heat exchanger portion without disturbing the remainder of the assembly. For instance, nut 30 may be removed to disassemble head member 21 from tube sheet 10 without affecting shell 14 which may be retained under fluid pressure if desired. 1 The absence of the usual bolt flanges in the heat exchangers of the present invention reduces manufacturing cost and provides a heat exchanger of a given rated size and capacity which is more compact in the direction of its diameter. Furthermore, internal pressure forces against the heads or end walls of such heat exchanger produce bending moments and flexural stresses which are of greatest magnitude at the centers of such head members or end walls. The tie rod arrangement of the foregoing embodiment minimizes the strains resulting from such flexural forces since the tie rod, in effect, cuts the beam posed against the other face of said tube sheet, a tie rod fixed medially to said tube sheet and extending axially in opposite directions through said shell and the closed end thereof and through said head member, and nut means engaging the opposite ends of said tie rod to bear against said shell and said head member to retain the same securely against said tube sheet.

2. In a heat exchanger, a tubular shell having an open end and a closed end, a tube sheet having one face thereof disposed against said open end and a plurality of U- tubes having their ends engaging perforations in said tube sheet and extending into said shell, a head member having an open end disposed against the other face of said tube sheet and a transverse Wall dividing the head member into inlet and outlet chambers, a tie rod fixed to said tube sheet and extending axially in opposite directions through the closed end of said shell and through said head member, and nut means engaging the opposite ends of said tie rod to bear against the closed end of said shell and against said head member to retain the same securely against said tube sheet.

3. In a heat exchanger, a tubular shell having an open end and a closed end, a tube sheet having one face thereof disposed against said open end and a plurality of U- tubes having their ends assembled with perforations in said tube sheet and extending into said shell, a cup-shaped head member having its open end disposed against the other face of said tube sheet, tie rod means fixed to said tube sheet and extending axially in opposite directions through said shell and the closed end thereof and through said head member, and nut means engaging the opposite ends of said tie rod means to bear against said shell and said head member to retain the same securely against said tube sheet.

4. In a heat exchanger, a tubular shell having an open end and a closed end, a tube sheet having one face thereof disposed against said open end and a plurality of U- tubes having their ends assembled with perforations in said tube sheet and extending into said shell, a cupshaped head member having its open end disposed against the other face of said tube sheet, a pass plate in said head member dividing the same into inlet and outlet chambers, the opposite ends of each U-tube engaging said tube sheet at opposite sides of said pass plate, a tie rod fixed medially to said tube sheet and extending axially in opposite directions through said shell and the closed end thereof and through said head member, and nut means engaging the opposite ends of said tie rod to bear against said shell and said head member to retain the same securely against said tube sheet.

5. A heat exchanger as set forth in claim 4, together with locating means between said head member and said tube sheet establishing and maintaining angular alinement therebetween.

6. A heat exchanger as set forth in claim 5, wherein said locating means comprise pin means laterally offset from said tie rod and extending between said tube sheet and said pass plate.

References Cited by the Examiner UNITED STATES PATENTS 839,867 1/1907 Miller -158 970,561 9/ 1910 Scaramuzza 165-158 1,739,018 12/1929 Shipley 165-158 2,661,934 12/1953 Stutz 165-72 KENNETH W. SPRAGUE, Primary Examiner.

FREDERICK L. MATTESON, ]R., Examiner. 

1. IN A HEAT EXCHANGER, A GENERALLY CYLINDRICAL SHELL HAVING AN OPEN END AND A CLOSED END, A TUBE SHEET HAVING ONE FACE THEREOF DISPOSED AGAINST SAID OPEN END AND A PLURALITY OF U-TUBES HAVING THEIR ENDS ASSEMBLED WITH PERFORATIONS IN SAID TUBE SHEET AND EXTENDING INTO SAID SHELL, A CUP-SHAPED HEAD MEMBER HAVING ITS OPEN END DISPOSED AGAINST THE OTHER FACE OF SAID TUBE SHEET, A TIE ROD FIXED MEDIALLY TO SAID TUBE SHEET AND EXTENDING AXIALLY IN OPPOSITE DIRECTIONS THROUGH SAID SHELL AND THE CLOSED END THEREOF AND THROUGH SAID HEAD MEMBER, AND NUT MEANS ENGAGING THE OPPOSITE ENDS OF SAID TIE ROD TO BEAR AGAINST SAID SHELL AND SAID HEAD MEMBER TO RETAIN THE SAME SECURELY AGAINST SAID TUBE SHEET. 